1. Field of the Invention
The present invention relates to a video signal processor, which properly suppresses color signals of, for example, R (red), G (green), B (blue), etc. without impairing white balance.
2. Description of the Related Art
As is generally known, in an apparatus, which displays various videos such as TV (television) receivers, processing to amplify R, G, B and other color signals and to adapt them to the dynamic range of a display unit is carried out.
For this kind of device, for example, in Jpn. Pat. Appln. KOKAI Publication No. 2002-64839, a peak clip circuit which carries out clip operation without impairing white balance is disclosed.
In this publication, when the maximum value in three color signals of R, G, and B is detected and the maximum value exceeds the displayable level, clipping is made with care to prevent white balance from being impaired by attenuating the maximum value to the displayable level and applying the same attenuation rate to other two colors.
In the publication mentioned above, it is possible to prevent white balance from being impaired but I/O characteristics, which unnaturally vary in the vicinity of displayable level result.
To describe specifically, when the maximum level of input signal does not reach the displayable level, the signal is outputted as it is.
On the contrary, when the maximum level of input signal exceeds the displayable level, attenuating operation works and by the attenuation operation, input signals have the level, for example, the level of the portion slightly exceeding the displayable level, attenuated to a level smaller than this displayable level.
Consequently, for example, in the event that three color signals of R, G, B that correspond to a color video in one frame are inputted, and the maximum level in these color signals fluctuates up and down, the outputted signal does not reflect this up and down fluctuation characteristics but the portion in which the input level forms a high peak is conversely suppressed to be low.
That is, the invention according to this publication may provide output characteristics, which do not properly reflect input characteristics in the vicinity of the boundary to choose whether or not the attenuation operation, should be carried out.